AddThis is a free IE toolbar that makes it easy to share the website you're viewing with others.
If you're at a page that you think it worth highlighting, simply click Share, then the appropriate service - Facebook, say - and add a few words on why it's worth a look. The URL and your comments will then be automatically added to your Facebook stream, and anyone else interested can take a look.
The toolbar supports a huge number of services: these include AIM, Bebo, Delicious, Digg, Facebook, LinkedIn, MySpace, Reddit, Slashdot, Technorati, Twitter, and many, many more.
You can also use it to manage pages more locally, though, with options to print them, save them as favourites, maybe email the URL of a page to someone (although this didn't work on our system).
And you also get a handy Search option that will search Yahoo!, Wikipedia, Amazon or eBay for the keywords you specify.